package com.lagou.edu.factory;

import com.lagou.edu.annotation.Autowired;
import com.lagou.edu.annotation.Component;
import com.lagou.edu.annotation.Transaction;
import com.lagou.edu.pojo.Account;
import com.lagou.edu.utils.TransactionManager;
import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.SQLException;

/**
 * @author 应癫
 *
 *
 * 代理对象工厂：生成代理对象的
 */

@Component
public class ProxyFactory {


    @Autowired
    private TransactionManager transactionManager;

//    public void setTransactionManager(TransactionManager transactionManager) {
//        this.transactionManager = transactionManager;
//    }

    /*private ProxyFactory(){

    }

    private static ProxyFactory proxyFactory = new ProxyFactory();

    public static ProxyFactory getInstance() {
        return proxyFactory;
    }*/



    /**
     * Jdk动态代理
     * @param obj  委托对象
     * @return   代理对象
     */
    public Object getJdkProxy(Object obj) {

        // 获取代理对象
        return  Proxy.newProxyInstance(obj.getClass().getClassLoader(), obj.getClass().getInterfaces(),
                new InvocationHandler() {
                    @Override
                    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                        Method realMethod = obj.getClass().getMethod(method.getName(), method.getParameterTypes());
                        if(realMethod.isAnnotationPresent(Transaction.class)) {
                            return invokeInTransation(obj, method, args);
                        }
                        return method.invoke(obj,args);
                    }
                });

    }


    /**
     * 使用cglib动态代理生成代理对象
     * @param obj 委托对象
     * @return
     */
    public Object getCglibProxy(Object obj) {
        return  Enhancer.create(obj.getClass(), new MethodInterceptor() {
            @Override
            public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
                Method realMethod = obj.getClass().getMethod(method.getName(), method.getParameterTypes());
                if(realMethod.isAnnotationPresent(Transaction.class)) {
                    return invokeInTransation(obj, method, objects);
                }
                return method.invoke(obj,objects);
            }
        });
    }

    private Object invokeInTransation(Object obj,Method method, Object[] objects) throws Exception {
        Object result = null;
        try{
            // 开启事务(关闭事务的自动提交)
            transactionManager.beginTransaction();

            result = method.invoke(obj,objects);

            // 提交事务

            transactionManager.commit();
        }catch (Exception e) {
            e.printStackTrace();
            // 回滚事务
            transactionManager.rollback();

            // 抛出异常便于上层servlet捕获
            throw e;

        }
        return result;
    }
}
